Define the terms thrust and pressure. State their SI units.
The total force acting on a body perpendicular to its surface is called thrust.
SI unit of thrust is newton (N).
Thrust acting per unit on the surface area is called pressure.
Pressure = Thrust
The SI unit of pressure is Nm–2 or pascal (Pa).
Does the gravitational force between two bodies change, if a material body is placed between them?
In which direction does the force of gravitational attraction act?
The force of gravitational attraction acts along the line joining the centres of mass of the two bodies.
Does ‘G’ change with increasing height above the earth’s surface?
Value of G remains constant. Therefore, the value of G does not change with increasing or decreasing height.
The moon's mass is approximately 1% of the earth's mass. How does the gravitational pull of the earth on the moon compare with the gravitational pull of the moon on the earth?
The gravitaional pull on both moon and Earth are equal because the value of 'g' is constant.